Income Taxes - Operating Loss and Tax Credit Carryforwards (Details) $ in Millions	Dec. 30, 2017 USD ($)
State
Operating loss and tax credit carryforwards
Operating loss carryforwards	$ 44.1
Tentative minimum tax credit carryforwards	0.1
Research and development tax credit carryforwards	13.4
Silicon Clocks, Spectra Linear and Ember | Federal
Operating loss and tax credit carryforwards
Operating loss carryforwards	37.5
Research and development tax credit carryforwards	1.9
Energy Micro | Foreign
Operating loss and tax credit carryforwards
Operating loss carryforwards	$ 9.6